SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e34389aa93ffdcec0ae6a04ab246af4f0b936e0624e2ccb97291b679bfb8d8d2' 
  AND token = 'pb0/uQbBIoxvMWY0t53GFxcREUGscvzJ6Ie9rq3sZpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}